From mboxrd@z Thu Jan 1 00:00:00 1970 From: francois@avalenn.eu Subject: Re: Time-zone in dates Date: Fri, 26 Jun 2015 21:57:49 +0200 Message-ID: <20150626195749.GG5090@fjo-extia-HPdeb> References: <87zj3moadx.fsf@gmail.com> <87zj3mv9rb.fsf@ucl.ac.uk> <87ioaav72g.fsf@ucl.ac.uk> <87y4j6tgyn.fsf@nicolasgoaziou.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:38986) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z8ZoO-000898-0Y for emacs-orgmode@gnu.org; Fri, 26 Jun 2015 16:01:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z8ZoN-0004kz-1O for emacs-orgmode@gnu.org; Fri, 26 Jun 2015 16:01:19 -0400 Received: from relay3-d.mail.gandi.net ([2001:4b98:c:538::195]:55388) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z8ZoM-0004hm-Rm for emacs-orgmode@gnu.org; Fri, 26 Jun 2015 16:01:18 -0400 Received: from localhost (unknown [IPv6:2a01:e35:8a40:5f00:1acf:5eff:fe3f:aff1]) (Authenticated sender: francois@avalenn.eu) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id 14D5FA80AC for ; Fri, 26 Jun 2015 22:01:13 +0200 (CEST) Content-Disposition: inline In-Reply-To: <87y4j6tgyn.fsf@nicolasgoaziou.fr> List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org Sender: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org To: emacs-orgmode@gnu.org Hello, On Fri, Jun 26, 2015 at 09:20:00PM +0200, Nicolas Goaziou wrote: > Time zone information is interesting when users of different areas are > exchanging Org documents. >=20 > I think it would be useful to have: >=20 > - a keyword to specify time zone per document. This time zone would > apply to every time stamp not defining their own time zone. Default > value could be `local' so we would be backward compatible. >=20 > - a way to specify a time zone per time stamp, overriding the previous > keyword. >=20 > I think it would require to define a proper API for timestamps in order > to ensure, e.g., comparisons are done right. Timezones are strange beasts to deal with. It is really simpler programmatically to deal with time offsets instead. The downside is that you cannot manage DST and other similar peculiarities but the API is much simpler to write. Just please don't confuse timezones and time offsets especially in documentation as it is not the same thing and it can lead to confusion. I reread from time to time this note from W3C which explains the difference and why it matters : http://www.w3.org/TR/2005/NOTE-timezone-20051013/#d2e226=20 Regards, Fran=E7ois